In my career as a physical therapist, I have yet to find more than a handful of runners with adequate hip flexor length. I have found most runners to be consistent with stretching for their hamstrings, calves, and piriformis (I will get on my soap box about this little guy in another blog), but unfortunately they are less consistent with stretching the muscles that flex the hip.

Tightness in the hip flexors can be an accomplice to a host of aliments such as lower back pain, IT band syndrome, femoroacetabular impingement, and hip bursitis. From a performance standpoint, hip flexor tightness limits stride length and efficiency. In order to “balance the hip”, runners should consistently stretch their hip flexors and strengthen their gluteus maximus and medius. I have spoken about the gluteal muscles previously and therefore will address the anterior hip tightness presently.

Where Are The Hip Flexors Anyway?

For those who have not taken anatomy 101 locating all the hip flexors can be a challenge. There are 3 major muscles that flex the hip. The iliacus, psoas major, and rectus femoris (there are others but they are not big players). Many refer to the hip flexor as the iliopsoas which can be confusing considering it is a combination of two of the three hip flexor muscles. The iliacus and the psoas major. The iliacus resides on the inside of your ilium, the large hip bone that you grab when you “put your hands on your hips”. The psoas travels a lengthier path from the front of your spine, T12 and lumbar transverse process levels 1-5, and attaches on the lesser trochanter of the femur. Since they insert on the femur at the same location and have a common iliac fascia they are affectionately combined as the iliopsoas.

The rectus femoris originates from the anterior inferior iliac spine and inserts, via the quadriceps and patellar tendon, to the tibial tuberosity.

http://www.musclesused.com/quadriceps/

Actions of The Hip Flexors

Hip Flexion

The primary job of the hip flexors are of course to flex the hip. This is a vital action for gait, stair climbing, dressing, and getting into a car. This primary action takes place when the trunk is stationary giving the flexors a bracing point to pull up on the leg. The fatigue you feel in your anterior hip when doing bicycles for your abdominals is due to the action of the hip flexors pulling your legs towards your torso.

Trunk Flexion

If we reverse the above scenario so the leg component is stationary then the hip flexors will create lumbar flexion. To clarify further, bilateral action of the hip flexors will create lumbar flexion while unilateral action will create lumbar side bending.

Hip Adduction and External Rotation

Additionally, the iliopsoas action will change based on the orientation of the femur. When the hip is in flexion, the iliopsoas acts as an adductor of the hip pulling the femur towards the center of the body. When the hip is in neutral, the iliopsoas flexes and laterally rotators the femur (although the lateral rotation is very small).

Lumbar Extension and Anterior Pelvic Tilt

In hip extension, during walking or running, tension in the hip flexors will create anterior tilting of the pelvis and lumbar extension due to the anterior pull on the lumbar vertebrae. This happens to be a large cause of back pain in those with lumbar stenosis or extension sensitivity which we will discuss later.

2 Common Hip Flexor Pathologies

Tendonitis/Tendinosis

The common complaints from hip flexor tendinopathy include anterior hip pain, lower back pain, and burning or referred pain down the anterior thigh. Acutely, the pain is sharp and located right over the anterior hip bone. As the issue becomes more chronic it will present with a dull to moderate ache along the anterior hip and thigh.

We have all heard the term tendonitis before. Tendonitis refers to an overuse syndrome in which inflammatory cells are present leading to the symptom of pain.

Tendonitis is an acute condition which arises quickly from a specific action or series of actions. In the initial stages, it is treated with cessation of the aggravating activity, rest, ice, and anti-inflammatory medications. Following a few days of TLC it is important to address the underlying factors that caused the overuse to occur. This may be biomechanical movement errors, improper training, weakness, or lack of mobility.

If a tendonitis is allowed to continue without proper treatment it can become a tendinosis. Tendinosis refers to chronic irritation of the tendon with tissue damage noted at the cellular level. The key difference between the two pathologies is that in tendinosis there is a lack of inflammatory mediators within the tissue. Additionally, a chronically overused tendon can become compliant, meaning it loses its natural tension making it harder for the muscle to pull on the tendon for action.

If you have had an episode of tendonitis at the hip flexor and the pain has continued for more than 8 weeks then it has likely become a tendinosis. Treating a tendinosis does not require the initial rest phase but rather specific training to improve tendon tissue quality, strength, and eccentric control.

Table 3. Implications of the diagnosis of tendinosis compared to tendinitis. Adapted from: “Overuse tendinosis, not tendinitis: Part 1: A new paradigm for a difficult clinical problem,” by Khan KM; Cook JL, et. al, 2000. The physician and Sportsmedicine, 28 (5) pg.4

Lower Back Pain

As previously mentioned, the iliopsoas attaches to the anterior surface of the lumbar transverse processes and can contribute to both lumbar flexion and extension. In most of the cases where altered hip flexor action and mobility are to blame, there is associated increased lumbar extension. Many occupations today require extensive amounts of sitting. During sitting, our hips will typically flexion between 80 to 110 degrees depending on your ergonomic step up, height, chair choice, and of course posture. The higher your knees are in relation to your pelvis the greater the hip flexion. This posture is not an issue if you were to sustain it for a couple of hours per day. It does become an issue when that positioning is maintained for 30-40 hours per week.

In a seated position the hip flexor resides in a shortened position since your anterior thigh is closer to your lumbar spine. Over time, and long durations of sitting, your hip flexors will prefer to be in a shortened versus anatomical length. This creates an issue once we are upright trying to walk, run, and play sports. In typical gait, we need approximately 20 degrees of hip extension. This number is usually slightly increased for running to about 25 degrees. If the hip flexor complex is tight, then it is not possible to fully achieve proper hip extension. From the outside it looks as though the hip is extending when internally compensation likely exists.

The typical compensatory pattern for hip flexor tightness is anterior pelvic tilting and increased lumbar lordosis. In laymen’s terms, the lower back is extended and the buttocks is sticking out and up. If the tightness is unilateral then anterior pelvic tilting is accompanied by ipsilateral pelvic drop and contralateral lumbar facet compression. This pattern of increased lumbar extension and side bending with gait is a large reason why those diagnosed with stenosis have a difficult time walking pain free.

How To Determine Hip Flexor Tightness

Now that we have seen how hip flexor tightness plays a role in tendonitis and lower back pain it is important to have a good way to assess hip flexor mobility. The gold standard test for assessing hip flexor mobility is the Thomas Test.

In the Thomas Test, the patient lies supine with their hips located at the end of a firm table. The practitioner has the patient bring the opposite knee to their chest and hold it there during testing. The practitioner then uses one hand to hold the lumbar spine and pelvis flush to the table while extending the leg on the side being tested. The key is stopping the test once any lumbar extension is felt (this is a sign that the hip flexors are at their limit and therefore pulling upwards on the anterior spine creating extension). At this point in the test the hip flexor angle is recorded. Generally speaking, a normal test would have the hip in a neutral or near neutral position (within 10 degrees). Studies on competitive athletes have shown 0-10 degrees of true hip extension (thigh below horizontal) as the norm.

The 3 Keys to the Best Hip Flexor Stretch

In my physical therapy career, I have found that one of the hardest stretches to teach is a proper hip flexor stretch. Although many people are familiar with variations of hip flexor stretching, most have altered form which makes the stretch less specific and of little value.

Controlling the pelvis, lumbar spine, and torso is key to a proper hip flexor stretch.

#1 Avoid an Anterior Pelvic Tilt

Anterior tilt of the pelvis with lumbar extension http://www.bodybuilding.com/fun/flex-those-flexors-3-steps-to-powerful-hips.html It is essential to maintain a neutral or slightly posteriorly tilted pelvis during the stretch. Since we know the rectus femoris attaches to the anterior inferior iliac spine of the ilium, stretching therefore will create an anterior pelvic tilting torque. If we give in to this force the stretch becomes an abdominal stretch since the lumbar spine will extend and the stomach will have an anterior arch.

If we resist the anterior pelvic tilt and try to posteriorly tilt the pelvis we effectively produce a stretch along the rectus femoris. A posterior pelvic tilt lifts the AIIS away from the distal attachment of the rectus femoris.

To further stretch the rectus femoris you can add knee flexion since the distal attachment goes through the quadriceps and patellar tendons.

#2 Avoid Lumbar Extension

Excessive lumbar extension limits the stretch on the iliopsoas

It is essential to keep a neutral lumbar spine to produce a proper hip flexor stretch. If we recall from our previous anatomy lesson, the iliopsoas attaches to the anterior aspect of the lumbar transverse processes. Tension in this tissue will produce lumbar lordosis or extension. A stretch is produced in the iliopsoas by resisting lumbar extension as the hip moves into extension.

It is helpful to use a mirror while doing a hip flexor stretch to observe pelvis and lumbar spine motion. I encourage people to use a dowel or stick positioned along their spine as biofeedback. I cue the patient by telling them, “keep your whole back and tail bone touching the stick”. This helps maintain both a neutral pelvis and lumbar spine.

#3 Add Contralateral Side Bending

To get the most bang for your buck with hip flexor stretching it is valuable to side bend away from the hip being stretched. Since we know unilateral hip flexor tightness produces ipsilateral lumbar side bending, we know that contralateral side bending will provide an additional stretch. This should be added to any hip flexor stretch.

This video demonstrates the changes in pelvis position by changing lumbar flexion and extension. Increased lumbar extension creates an anterior pelvic tilt limiting potential stretch on the hip flexors. By performing a posterior pelvic tilt the stretch on the hip flexors is optimized.

Finding the Balance

Having tight hip flexors myself, I can attest to the relief and freedom of having a balanced hip. If you are a runner and want to improve your running form then I suggest stretching your hip flexors after your runs for 2-3 minutes each side per day. Producing real change in tissue length takes a prolonged stretching routine over many weeks. If you have low back pain, anterior hip pain, or groin pain then performing a daily hip flexor stretch may help.

To fully balance the hip it is necessary to have proper gluteus activation and strength. By having a strong hip and buttocks and a flexible anterior hip you can run with more ease, less pain, and a better stride. At Competitive EDGE Physical Therapy I have helped other runners restore proper hip flexor length allowing them to run with improved range of motion and less back pain. Our state-of-the-art running specialty practice is built to help runners improve their stride, increase their strength, and run pain free.

If you would like to speak with a running specialist please call 408-784-7167 or email Kevin@compedgept.com

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